Solve the example problem in Sec. 11.5.4, but assume that the seismic zone = 1. Compare the results with the solution to the example problem in Sec. 11.5.4.

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Accepted Answer

Use the following data: soil profile type = [latex]S _{ C }[/latex] and seismic zone = 1.

1. Seismic coefficient [latex]C_{a}[/latex] (Table 11.2): Entering Table 11.2 with soil profile type [latex]C_{C}[/latex] and zone 1, the value of [latex]C_{a}[/latex] = 0.09.
2. Seismic coefficient [latex]C_{v}[/latex] (Table 11.5): Entering Table 11.5 with soil profile type [latex]S_{C}[/latex] and zone 1, the value of [latex]C_{v}[/latex] = 0.13.
3. Values of [latex]T_{s} ext { and } T_{0}[/latex] [Eqs. (11.5) and (11.6)]: The values of [latex]T_{s} ext { and } T_{0}[/latex] can be calculated as follows:

[latex]T_{S}=\frac{C_{v}}{2.5 C_{a}}=\frac{0.13}{2.5(0.09)}=0.58 s[/latex]
[latex]T_{0}=0.2 T_{s}=0.20(0.58)=0.12 s[/latex]

By using Fig. 11.10 and the values [latex]C_{a}=0.09, C_{v}=0.13, T_{s}=0.58 s , ext { and } T_{0}=0.12 s[/latex], the response spectrum can be determined and is shown in Fig. 11.20.

TABLE 11.2 Seismic Coefficient [latex]C_{a}[/latex]
Soil profile type	Seismic zone (see Fig. 5.17)
Soil profile type	Zone 1	Zone 2A	Zone 2B	Zone 3	Zone 4
[latex]S_{A}[/latex]	0.06	0.12	0.16	0.24	0.32 [latex]N_{a}[/latex]
[latex]S_{B}[/latex]	0.08	0.15	0.20	0.30	0.40 [latex]N_{a}[/latex]
[latex]S_{C}[/latex]	0.09	0.18	0.24	0.33	0.40 [latex]N_{a}[/latex]
[latex]S_{D}[/latex]	0.12	0.22	0.28	0.36	0.44 [latex]N_{a}[/latex]
[latex]S_{E}[/latex]	0.19	0.30	0.34	0.36	0.44 [latex]N_{a}[/latex]
[latex]S_{F}[/latex]	Soil requiring a site-specific evaluation (see Sec. 11.5.2)

TABLE 11.5 Seismic Coefficient [latex]C_{v}[/latex]
Soil profile type	Seismic zone (see Fig. 5.17)
Soil profile type	Zone 1		Zone 2A	Zone 2B	Zone 3	Zone 4
[latex]S_{A}[/latex]	0.06	0.12		0.16	0.24	0.32 [latex]N_{v}[/latex]
[latex]S_{B}[/latex]	0.08	0.15		0.20	0.30	0.40 [latex]N_{v}[/latex]
[latex]S_{C}[/latex]	0.13	0.25		0.32	0.45	0.56 [latex]N_{v}[/latex]
[latex]S_{D}[/latex]	0.18	0.32		0.40	0.54	0.64 [latex]N_{v}[/latex]
[latex]S_{E}[/latex]	0.26	0.50		0.64	0.84	0.96 [latex]N_{v}[/latex]
[latex]S_{F}[/latex]	Soil requiring a site-specific evaluation (see Sec. 11.5.2)
Data obtained from the Uniform Building Code (1997). Obtain [latex]N_{v}[/latex] from Table 11.6.

TABLE 11.6 Near-Source Factor [latex]N_{v}[/latex]
Seismic source type (see Table 11.4)	Closest distance to known seismic source
Seismic source type (see Table 11.4)	≤ 1.2mi (≤2 km)	3 mi (5 km)	6 mi (10 km)	≥ 9 mi (≥ 15 km)
A	2.0	1.6	1.2	1.0
B	1.6	1.2	1.0	1.0
C	1.0	1.0	1.0	1.0
Notes: Data obtained from the Uniform Building Code (1997). Near-source factor [latex]N_{v}[/latex] is only needed if the seismic zone = 4 (see Table 11.5). The near-source factor may be based on the linear interpolation of values for distances other than those shown in the table. The location and type of seismic sources to be used for design can be based on geologic data, such as recent mapping of active faults by the U.S. Geological Survey or the California Division of Mines and Geology. The closest distance to the known seismic source can be calculated as the minimum distance between the site and the surface location of the fault plane (or the surface projection of the fault plane). If there are several sources of seismic activity, then the closest one to the site should be considered to be the governing case.

TABLE 11.4 Seismic Source Type
Seismic source type	Seismic source definition
Seismic source type	Seismic source description	Maximum moment magnitude [latex]M_{w}[/latex] ≥ 7	Slip rate, mm/yr
A	Faults that are capable of producing large-magnitude events and that have a high rate of seismic activity	[latex]M_{w}[/latex] ≥ 7	SR ≥ 5
B	All faults other than types A and C	[latex]M_{w}[/latex] ≥ 7	SR < 5
		[latex]M_{w}[/latex] < 7	SR > 2
		[latex]M_{w}[/latex] ≥ 6.5	SR < 2
C	Faults that are not capable of producing large-magnitude earthquakes and that have a relatively low rate of seismic activity	[latex]M_{w}[/latex] < 6.5	SR ≤ 2
Notes: Data obtained from the Uniform Building Code (1997). Seismic source type is only needed if the seismic zone = 4 (see Table 11.2). Subduction sources shall be evaluated on a site-specific basis. For the seismic source definition, both the maximum moment magnitude [latex]M_{w}[/latex] and slip rate (SR) conditions must be satisfied concurrently when determining the seismic source type.

Question 11.2: Solve the example problem in Sec. 11.5.4, but assume that th...

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